The p-Aminophenol you will easily get is likely the salt of
Hydrochloric Acid or maybe the sulfate, but AFAIK only rarely the free base. Fortunately it doesn't matter much, the few extra chloride ions will not matter much except for one thing: acidity. p-Aminophenol is a strong base, comparable to metaborate or carbonate.
Since your soup already uses Sodium Metaborate, I recommend the following:
- Get the much easier available p-Aminophenol Hydrochloride
- Substitute the free base mol for mol with the hydrochloride
- Take the number of mols you just calculated and add the same number of mols of Sodium Metaborate to the formula
This should get you at least into the ballpark.